Answer
m = 3 x $10^{21}$ g
Work Step by Step
m = d x V
The density of ice is given 0.917 g/cm3.
To find the volume of ice we have to find first the surface that is covered by ice, and than the volume of the ice.
Surface covered by ice: 840,000 $mi^{2}$ - 132,000 $mi^{2}$ = 708,000 $mi^{2}$.
Converted this surface : 708,000 $mi^{2}$ x $\frac{(5,280 ft)^{2}}{1 mi^{2}}$= 7.08 x $10^{5}$ x 28 x $10^{6}ft^{2}$= 198 x $10^{11}ft^{2}$
Volume V = surface x height (thickness)
V = 198 x $10^{11}ft^{2}$ x 5 x $10^{3}$ft
V = 990 x$10^{14}ft^{3}$
V = 990 x$10^{14}ft^{3}$ x $\frac{(12in)^{3}}{1 ft^{3}}$ x $\frac{(2.54cm)^{3}}{1in^{3}}$
V = 2.8 x $10^{21}cm^{3}$
m = d x V
m = 0.917 $\frac{g}{cm^{3}}$ x 2.8 x $10^{21}cm^{3}$
m = 2.6 x $10^{21}$ g or m = 3 x $10^{21}$ g
